глупый трекер контента (the stupid content tracker)
SYMBOLIC IDENTIFIERS
Any Git command accepting any <object> can also use the following
symbolic notation:
HEAD
indicates the head of the current branch.
<tag>
a valid tag name (i.e. a refs/tags/<tag> reference).
<head>
a valid head name (i.e. a refs/heads/<head> reference).
For a more complete list of ways to spell object names, see
"SPECIFYING REVISIONS" section in gitrevisions(7).
